이 콘텐츠는 선택한 언어로 제공되지 않습니다.

2.3. Library Bundle


Overview

This section explains how to set up a Maven project for a typical library bundle.
The time-util bundle exemplifies a library bundle, where the main purpose of a library is to make interfaces and classes available to other bundles. Hence, the library should export all of its own packages and associate a version number with the exported packages.

Directory structure

Assuming it is built as a Maven project, the time-util bundle has the following directory structure:
time-util/
  |
  \--src/
     |
     \--main/
     |  |
     |  \--java/
     |     |
     |     \--org/fusesource/example/time/
     |        |
     |        \-TimeUtil.java
     |        |
     |        \-Clock.java
     |   
     \--test/
Copy to Clipboard Toggle word wrap
The Java source code is located under the src/main/java sub-directory. The org.fusesource.example.time package is public and all of its classes and interfaces can be exported from the bundle.
There are no blueprint resources associated with this bundle.

Sample implementation

The time-util bundle is essentially a wrapper around some of the standard time utilities in Java. It provides a Clock class, which returns the local time in a particular time zone when you invoke the Clock.getLocalTime() method. The Clock class is defined as follows:
// Java
package org.fusesource.example.time;

import java.util.Calendar;
import java.util.Locale;
import java.util.TimeZone;

public class Clock {
    ...    
    public Clock(TimeUtil.TimeZone tz) {
        ...
    }
    
    public String getLocalTime() {
        return jcal.getTime().toString();
    }
}
Copy to Clipboard Toggle word wrap
The TimeUtil class is a factory that is used to create Clock instances for particular time zones. Two time zones are supported: TimeZone.BOSTON and TimeZone.PARIS. The TimeUtil class is defined as follows:
// Java
package org.fusesource.example.time;

public class TimeUtil {
  public enum TimeZone {
    BOSTON,
    PARIS
  }

  public static Clock createClock(TimeZone tz) {
      return new Clock(tz);
  }
}
Copy to Clipboard Toggle word wrap

Import and export rules

The following import and export rules apply to the time-util bundle:
  • Exporting own packages—the org.fusesource.example.time package is public, and must be exported.
  • Importing own packages—none of the bundle's own packages should be imported, which is the usual case for a library bundle.
  • Importing dependent packages—any external package dependencies must be imported. In this particular example, however, there are none (the time-util bundle depends only on classes from the JVM).

Maven bundle plug-in settings

The Maven bundle plug-in is configured to export the library package, org.fusesource.example.time (coded as ${project.groupId}.time). The Export-Package instruction also contains entries to block the export of any packages containing .impl or .internal. In this case, the bundle plug-in instructions are as follows:
<instructions>
  <Bundle-SymbolicName>${project.groupId}.${project.artifactId}</Bundle-SymbolicName>
  <Import-Package>*</Import-Package>
  <Export-Package>
    !${project.groupId}*.impl*,
    !${project.groupId}*.internal*,
    ${project.groupId}.time*;version=${project.version}
  </Export-Package>
</instructions>
Copy to Clipboard Toggle word wrap

Generated MANIFEST.MF file

When you build the bundle using Maven, the Maven bundle plug-in automatically generates the following MANIFEST.MF file:
Manifest-Version: 1.0
Bundle-Name: time-util
Built-By: JBLOGGS
Build-Jdk: 1.5.0_08
Created-By: Apache Maven Bundle Plugin
Bundle-ManifestVersion: 2
Bundle-SymbolicName: org.fusesource.example.time-util
Tool: Bnd-1.15.0
Bnd-LastModified: 1297357076457
Export-Package: org.fusesource.example.time;version="1.0"
Bundle-Version: 1.0.0
Copy to Clipboard Toggle word wrap
맨 위로 이동
Red Hat logoGithubredditYoutubeTwitter

자세한 정보

평가판, 구매 및 판매

커뮤니티

Red Hat 문서 정보

Red Hat을 사용하는 고객은 신뢰할 수 있는 콘텐츠가 포함된 제품과 서비스를 통해 혁신하고 목표를 달성할 수 있습니다. 최신 업데이트를 확인하세요.

보다 포괄적 수용을 위한 오픈 소스 용어 교체

Red Hat은 코드, 문서, 웹 속성에서 문제가 있는 언어를 교체하기 위해 최선을 다하고 있습니다. 자세한 내용은 다음을 참조하세요.Red Hat 블로그.

Red Hat 소개

Red Hat은 기업이 핵심 데이터 센터에서 네트워크 에지에 이르기까지 플랫폼과 환경 전반에서 더 쉽게 작업할 수 있도록 강화된 솔루션을 제공합니다.

Theme

© 2025 Red Hat